Programming Questions

Q:

Point out the error, if any, in the following program.

# include "stdio.h"

main()

{

     FILE *fp;

     char str[80];

     fp = fopen ("trail", "r");

     while (!feof (fp))

    {

           fgets (str, 80, fp);

           puts (str);

     }

     fclose (fp);

}

Answer

The last line from the file "trial" would be read twice. To avoid this, ues:


       While ( fgets (str, 80, fp) ! = NULL)


               puts (str);

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Subject: Programming

0 1608
Q:

Write a c program for binary search.

Answer

#include<stdio.h>
int main(){

    int a[10],i,n,m,c=0,l,u,mid;

    printf("Enter the size of an array: ");
    scanf("%d",&n);

    printf("Enter the elements in ascending order: ");
    for(i=0;i<n;i++){
         scanf("%d",&a[i]);
    }

    printf("Enter the number to be search: ");
    scanf("%d",&m);

    l=0,u=n-1;
    while(l<=u){
         mid=(l+u)/2;
         if(m==a[mid]){
             c=1;
             break;
         }
         else if(m<a[mid]){
             u=mid-1;
         }
         else
             l=mid+1;
    }
    if(c==0)
         printf("The number is not found.");
    else
         printf("The number is found.");

    return 0;
}

Sample output:
Enter the size of an array: 5
Enter the elements in ascending order: 4 7 8 11 21
Enter the number to be search: 11
The number is found.

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Subject: Programming

0 1605
Q:

Indicate what would the SWAP macro be expanded to on preprocessing. Would the code compile?

#define SWAP (a, b, c ) (c t; t = a, a = b, b = t; )

main()

{

    int x = 10, y = 20;

    SWAP (x, y, int );

    printf ( " %d%d ", x, y);

}

Answer

( int t ; t = a, a = b, b = t ;);


This code won't compile since declaration of t cannot occur within parentheses.


 

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Subject: Programming

0 1588
Q:

In the following code can we declare a new typedef name emp even though struct employee has not been completely defined while using typedef? < Yes / No>

typedef struct employee *ptr;

struct employee

{

       char name[20];

        int age;

        ptr next;

};

Answer

Yes

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Subject: Programming

0 1570
Q:

What will be output of following c code?

void main()
{
struct bitfield
{
unsigned a:5;
unsigned c:5;
unsigned b:6;

}bit;
char *p;
struct bitfield *ptr,bit1={1,3,3};
p=&bit1;
p++;
clrscr();
printf("%d",*p);
getch();
}

Answer

Output: 12

Explanation:
Binary value of a=1 is 00001 (in 5 bit)
Binary value of b=3 is 00011 (in 5 bit)
Binary value of c=3 is 000011 (in 6 bit)

In memory it is represented as:
Let address of bit1 is 500 which initialize to char pointer p. Since can is one byte data type so p++ will be 501. *p means content of memory location 501 which is (00001100) and its binary equivalent is 12. Hence output is 12.

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Subject: Programming

0 1518
Q:

Improve the following code using typedef.

struct node

{

      int data1;  float data2;

       struct node *left;

       struct node *right;

};

struct node *ptr;

ptr = (struct node *) malloc (sizeof (struct node) ); 

Answer

typedef struct node * treeptr


typedef struct node


{


         int data1;


         float data2;


         treeptr *left;


         treeptr *right;


}treenode;


treeptr ptr;


ptr = ( treeptr ) malloc ( sizeof ( treenode ) );

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Subject: Programming

0 1510
Q:

What would be the output of the following program?

main()

{

     char ch ='A';

      printf ("%d%d", sizeof (ch), sizeof ('A'));

}

Answer

1   2

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Subject: Programming

0 1493
Q:

How many times the following program would print 'Jamboree'?

main()

{

     printf ( "\nJamboree");

     main ();

}

Answer

Till the stack doesn't overflow

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Subject: Programming

1 1449